1. Field of the Invention
This invention relates to transport aircraft galley systems, and more particularly, to systems to cool food carts prior to service by the cabin attendants.
2. General Background and State of the Art
Aircraft galley systems for modern transport aircraft incorporate food carts which are cooled to prevent food spoilage prior to use by the cabin attendants for distribution of food to the passengers. These food carts have in the past been interfaced with cold air supply systems in the galley designed to cool the interiors of the food carts. Such cool air distribution systems were generally co-located with the balance of the galley and interface with the food carts by means of gaskets connecting the food carts to a plenum providing the cool air. Conventional galley refrigeration systems typically utilize self contained air chillers which provide the cooled air directly to the food carts or refrigerated compartments. Such air chillers are typically installed above, below or otherwise within close proximity of the galley, and deliver cooled air via air ducts.
Chilling systems with remotely located liquid chillers have been developed that chill a heat transfer liquid that enters galley air cooling system devices, where heat is transferred from the compartment air to the liquid. However, since a cooled liquid is circulated, the liquid bus must be carefully insulated. As space in modern aircraft has become more at a premium and more efficient means of cooling the carts has become necessary, there has emerged a need for more efficient alternatives to such systems. Furthermore, recent FDA rulings have lowered the required temperature at which the interior of the food carts has to be kept in order to prevent food spoilage. It is important that any system that interfaces with either food or the cabin area can be configured to provide a wide range of cooling capacity as a function of the food and food carts that are to be interfaced with such a system.
Additionally, it has become more desirable to remove refrigeration equipment from the galley compartment and to find other means to properly cool the food carts without locating the entire refrigeration system in the galley area. In order to be compatible with modern transport aircraft requirements, it has become important to have an increased degree of safety and modularity for any aircraft system incorporating electronics or electric pumps, and it would be particularly desirable to locate at least a portion of such systems outside of the cabin area of the aircraft. In any event, it is important that any system that interfaces with either food or the cabin area is non-toxic and can be configured to provide a wide range of cooling capacity as a function of the food and food carts that are to be interfaced with such a system.
Aircraft air chillers are typically rated for operation at ambient temperatures of 85° F., and are capable of operating for short periods of time at ambient temperatures of up to 130° F. However, above 85° F., ambient refrigeration capacity decreases, and at 130° F., ambient refrigeration capacity is reduced approximately 60 percent. In addition, when the air chillers are not mounted within the cabin of an aircraft, the air chillers commonly do not provide adequate condenser airflow and cooling efficiency when the aircraft are on the ground in hot ambient temperatures, producing high condenser inlet temperatures. Furthermore, high operating temperatures that can occur under such conditions typically lead to higher failure rates and premature wear.
While one solution to the problem of providing adequate cooling at such elevated temperatures would be to provide an air chiller with a higher cooling capacity that would be adequate at these elevated temperatures, this would result in a significantly heavier air chiller unit which would be unacceptable for use in aircraft, and which would consume more power and would be considerably more expensive. A concomitant problem of providing such a higher capacity air chilling unit would be the requirement of removing an increased condenser airflow.
The present invention satisfies these and other requirements for aircraft galley systems.